Field of the Invention
The invention relates to an exposure adjusting method and an electronic apparatus using the same, and particularly relates to a dynamic exposure adjusting method and an electronic apparatus using the same.
Description of Related Art
Most of the electronic apparatuses that are capable of taking pictures, such as digital cameras or smart phones, are now provided with the high dynamic range (HDR) function. When the HDR function is activated, the electronic apparatuses are allowed to improve the display of the bright and shadow details. Thus, objects in the picture are clear.
The conventional HDR technique mainly serves to obtain the best display when taking a picture. Namely, shadow details of the picture should be clear and there should be no over exposure in a bright scene. Thus, when taking the picture, a plurality of pictures having different exposure values are to be combined to form a preferable HDR picture. First of all, to obtain clear shadow details, the electronic apparatus may take a picture with a long exposure, so that a darker region in the scene becomes brighter. Then, in the same scene, the electronic apparatus may take a picture with a short exposure, so that a brighter region in the scene becomes darker to avoid over exposure.
Referring to FIG. 1, FIG. 1 is a schematic view illustrating the conventional high dynamic range (HDR) technology. When the electronic apparatus takes a picture with the HDR function activated, the electronic apparatus may simultaneously take pictures 110, 120, and 130. The picture 110 is a short exposure picture taken based on an exposure value (EV) of ½, for example, which is used to shoot a part having a higher brightness in the scene (e.g. region 115). The picture 120 is a normally exposed picture taken by the electronic apparatus based on an exposure value of 1 EV. The picture 130 is a long exposure picture taken based on an exposure value of 2 EV, for example, which is used to shoot a part having a lower brightness in the scene (e.g. region 135). Then, the electronic apparatus may combine the pictures 110, 120, and 130 to form a picture 140. Thus, the picture 140 may simultaneously show clear shadow details and have no over exposure in the bright scene.
However, in the conventional technology, it is common to use fixed values for the long and short exposure times (e.g. ½ EV and 2 EV as described above). In other words, regardless of the scene, the electronic apparatus consistently uses the fixed short exposure time and long exposure time to execute the HDR function when taking pictures. Taking FIG. 1 as an example, the HDR mechanism described therein takes three pictures based on ½ EV, 1 EV, and 2 EV during every shooting, and combining the three pictures as the final picture.
Thus, in some extreme scenes (e.g. taking a human image in a severe backlight environment), the HDR function may be almost ineffective when the electronic apparatus takes a picture with the HDR function activated. Specifically speaking, the HDR function is not able to compensate for the human image and scene in the picture to obtain a preferable picture (e.g. clear shadow details and no over exposure in the bright scene).